A Honduran immigrant accused of selling crack in the Tenderloin went on trial Thursday in San Francisco, with his attorney telling the jury that human traffickers had forced his client to sell drugs under threat of his life.

The case of Rigoberto Valle, 23, puts District Attorney Kamala Harris in a potentially awkward position. On the one hand, she has been vocal about her emphasis on prosecuting human traffickers. On the other, Harris - a candidate for state attorney general - has also been vocal in support of cracking down on drug sales in the Tenderloin.

The prosecution of Valle also raises the volatile issue of illegal immigrants engaged in drug sales. Supporters of the city's sanctuary efforts say many immigrants are the victims of drug cartels and forced to sell once they are brought here.

Valle is subject to possible deportation after his trial, regardless of whether he is convicted, because authorities believe he is in the country illegally.

Prosecutor Richard Hechler, in his opening statement, told the jury that Valle was guilty, plain and simple. He said Valle sold two rocks of crack to an undercover officer on June 4 at Larkin Street and Golden Gate Avenue.

"This case is a sale of a controlled substance, crack cocaine, by that gentleman, that night," Hechler said.

Valle's attorney, deputy public defender Hadi Razzaq, told jurors that his client is a victim who was brought to San Francisco by smugglers after a grueling journey by freight car and desert hike. Once here, he was ordered to sell drugs or be killed, Razzaq said.

Razzaq said Valle, who is expected to testify in his own defense, had sold his house in Honduras to raise $1,500 for the trip to the United States. Once he got near San Francisco, the smugglers demanded $500 more, which Valle did not have, Razzaq said.

"They locked him up for three days, and on the fourth day in the Bay Area, they forced him to sell," Razzaq said.

He had been on the corner of Golden Gate and Larkin just 10 minutes when he was arrested, the defense lawyer said.

Razzaq said he would call an expert on human trafficking to support his defense of Valle. His client, he said, came from a village of about 100 houses, is illiterate and came to this country to support his family.

"He was terrified - he had been duped, he was essentially kidnapped and locked in a room for three days," Razzaq said. "He was quite literally in fear for his life."

Brian Buckelew, a spokesman for the district attorney's office, said that although Harris is sympathetic to the plight of the victims of human traffickers, Valle's defense has offered nothing but rhetoric to back his story.

"There hasn't been any kind of tender to us of any evidence that would be verifiable," Buckelew said. "This is what trials are for. It is not the practice of this office to throw cases away when there is not even a proffer of evidence to support the defense."